# SSUBSCRIBE

```json metadata
{
  "title": "SSUBSCRIBE",
  "description": "Listens for messages published to shard channels.",
  "categories": ["docs","develop","stack","oss","rs","rc","oss","kubernetes","clients"],
  "arguments": [{"display_text":"shardchannel","multiple":true,"name":"shardchannel","type":"string"}],
  "syntax_fmt": "SSUBSCRIBE shardchannel [shardchannel ...]",
  "complexity": "O(N) where N is the number of shard channels to subscribe to.",
  "group": "pubsub",
  "command_flags": ["pubsub","noscript","loading","stale"],
  "acl_categories": ["@pubsub","@slow"],
  "since": "7.0.0",
  "arity": -2,
  "key_specs": [{"begin_search":{"spec":{"index":1},"type":"index"},"find_keys":{"spec":{"keystep":1,"lastkey":-1,"limit":0},"type":"range"},"not_key":true}],
  "tableOfContents": {"sections":[{"id":"examples","title":"Examples"},{"id":"redis-enterprise-and-redis-cloud-compatibility","title":"Redis Enterprise and Redis Cloud compatibility"},{"id":"return-information","title":"Return information"}]}
}
```













Subscribes the client to the specified shard channels.

In a Redis cluster, shard channels are assigned to slots by the same algorithm used to assign keys to slots. 
Client(s) can subscribe to a node covering a slot (primary/replica) to receive the messages published. 
All the specified shard channels needs to belong to a single slot to subscribe in a given `SSUBSCRIBE` call,
A client can subscribe to channels across different slots over separate `SSUBSCRIBE` call.

For more information about sharded Pub/Sub, see [Sharded Pub/Sub](https://redis.io/docs/latest/develop/pubsub#sharded-pubsub).

## Examples

```
> ssubscribe orders
Reading messages... (press Ctrl-C to quit)
1) "ssubscribe"
2) "orders"
3) (integer) 1
1) "smessage"
2) "orders"
3) "hello"
```

## Redis Enterprise and Redis Cloud compatibility

| Redis<br />Enterprise | Redis<br />Cloud | <span style="min-width: 9em; display: table-cell">Notes</span> |
|:----------------------|:-----------------|:------|
| <span title="Supported">&#x2705; Standard</span><br /><span title="Supported"><nobr>&#x2705; Active-Active</nobr></span> | <span title="Supported">&#x2705; Standard</span><br /><span title="Supported"><nobr>&#x2705; Active-Active</nobr></span> |  |

## Return information

{{< multitabs id="ssubscribe-return-info" 
    tab1="RESP2" 
    tab2="RESP3" >}}

When successful, this command doesn't return anything. Instead, for each shard channel, one message with the first element being the string `ssubscribe` is pushed as a confirmation that the command succeeded. Note that this command can also return a -MOVED redirect.

-tab-sep-

When successful, this command doesn't return anything. Instead, for each shard channel, one message with the first element being the string 'ssubscribe' is pushed as a confirmation that the command succeeded. Note that this command can also return a -MOVED redirect.